A purposive sub-sample of patients (sampling strategy designed to include a wide range of views and experiences, including patients from each centre) will be interviewed by telephone after being invited to take part in the feasibility trial, using a topic guide (developed collaboratively with lay representatives, with an emphasis on encouraging patients to describe their own perspectives freely - a preliminary topic guide has been developed and is included with this application), exploring views on being invited to participate in research in which they are randomised to different treatment options. The interview would also invite views on conducting a trial of endotherapy versus surgery. Interviews will be audio-recorded with separate consent and transcribed verbatim by transcribers working to professional standards of confidentiality.